<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            background-color: #666;
        }
        .box {
            margin: 50px auto;
            width: 50px;
            height: 100px;
            border-radius: 50%;
            /* box-shadow: 0 0 10px 5px #fff; */
            background-color: #fff;
            animation: zoom 1s infinite ease-in-out;
        }

        @keyframes zoom {
            0% {
                width: 0px;
                height: 0px;
                opacity: 1;
            }

            100% {
                width: 200px;
                height: 200px;
                opacity: 0;
            }
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>